Return or returnless style fuel system


brenda053
04-04-2019, 12:31 AM
I have a 96 Cutlass Supreme 3.1L V6 that s fuel injected with an in tank electronic fuel pump.
Can anyone tell me if it's a return style system or if it's a returnless fuel system.

maxwedge
04-04-2019, 09:14 AM
It is the return type, comes off the pressure regulator.

Tech II
04-04-2019, 09:37 AM
Correct....there are two lines to the fuel rail, supply and return, with the return coming from the f/p regulator like Max said...

brenda053
04-04-2019, 07:56 PM
Should fuel be draining back into the tank if the switch is turned on so the fuel pump engages but did not spin the motor. Turned switch on, waited until fuel pump stopped humming, turned switch off and could hear fuel draining back into tank.

Also...had DTC codes P0102 Mat circuit low, P0122 throttle/peddle position sensor switch A low, P0171 system too lean bank 1 and P0300 random cylinder misfire.
I cleaned the maf and its cracked on the plastic side where the metal strips show in the "windows". The throttle body was also extremely dirty.
Am I correct to assume the car isn't pumping normal fuel (which causes it to drain back into tank) because the maf is bad...

maxwedge
04-04-2019, 08:36 PM
maf will not cause your fuel symptoms, get a gage on it, see what pressure holds after shut down, look inside the vacuum hose for traces of fuel, also.

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